I have stayed in several hostels in Rio de Janeiro over the years and Zbra is my top recommendation for Rio. The location is excellent, 1 block away from the beach and in Leblon which is the safest area in Rio. The staff was really friendly and went out of thier way to help me with everything from finding the best parties of the night to finding a doctor. Also the dorms have an extra locker next to the bed for valuables which is great. In the hostel bar you will meet lots of other travellers too
This hostel surprised with its beautiful entrance area and apartment theme. It's basically Barcelona style apartments on several floors used as hostel rooms with an apartment feel. Which is better than your typical hostel doorm in my opinion. There where two super nice large bathrooms in the apartment my room was in and it looked like a geniun apartment. I love the Ample location/area.
Excellent party hostel, very professional facilities like a safe in your dorm room with a key lock system for all facilities . I stayed in Kabul to be social and it's perfect for meeting people since they have their own bar at the hostel. Also the location gets no better if you want to live central.